Ultrafast Photooxidation Of Mn(ii)-terpyridine Complexes Covalently Attached To Tio2

Transcript

This paper reports visible-light sensitization of TiO2 nanoparticles by surface modification with Mn(II)- terpyridine complexes, as evidenced by UV-vis spectroscopy of colloidal thin films and aqueous suspensions. Photoexcitation of the [MnII(H2O)3(catechol-terpy)]2+/TiO2 (terpy ) 2,2¢:6,2¢¢-terpyridine) complex, attached to the TiO2 surface, leads to interfacial electron transfer within 300 fs as indicated by ultrafast optical pumpterahertz probe transient measurements and computational simulations. Photoinduced interfacial electron transfer is accompanied by Mn(II) f Mn(III) photooxidation. The half-time for regeneration of the Mn(II) complex is ca. 23 s (at 6 K), as monitored by time-resolved measurements of the Mn(II) EPR signal.